1. Field of the Invention
The present invention relates to an image-forming substrate coated with a layer of microcapsules filled with dye or ink, on which an image is formed by selectively breaking or squashing the microcapsules in the layer of microcapsules.
2. Description of the Related Art
In a conventional type of image-forming substrate coated with a layer of microcapsules filled with dye or ink, a shell of each microcapsule is formed from a suitable photo-setting resin, and an optical image is recorded and formed as a latent image on the layer of microcapsules by exposing it to light rays in accordance with image-pixel signals. Then, the latent image is developed by exerting a pressure on the layer of microcapsules. Namely, the microcapsules, which are not exposed to the light rays, are broken and squashed, whereby the dye or ink seeps out of the broken and squashed microcapsules, and thus the latent image is visually developed by the seepage of the dye or ink.
Of course, each of the conventional image-forming substrates must be packed so as to be protected from being exposed to light, resulting in wastage of materials. Further, the image-forming substrates must be handled such that they are not subjected to excess pressure due to the softness of unexposed microcapsules, resulting in an undesired seepage of the dye or ink.
Also, a color-image-forming substrate coated with a layer of microcapsules filled with different color dyes or inks, is known. In this substrate, the respective different colors are selectively developed on an image-forming substrate by applying specific temperatures to the layer of color microcapsules. Nevertheless, for fixing, it is necessary to irradiate a developed color using a light of a specific wavelength. Accordingly, a color-image-forming system for forming a color image on the color-image forming substrate is costly, because an additional radiation apparatus for the fixing of a developed color is needed, which in turn increases electric power consumption. Also, since a heating process for the color development and an irradiation process for the fixing of a developed color must be carried out with respect to each color, this hinders a quick formation of a color image on the color-image-forming substrate.
Therefore, an object of the present invention is to provide an easy-to-handle image-forming substrate coated with a layer of microcapsules filled with dye or ink, in which an image can be quickly formed on the image-forming substrate at a low cost.
In accordance with a first aspect of the present invention, there is provided an image-forming substrate comprising: a base member; and a layer of microcapsules, coated over the base member, that contains at least one type of microcapsules filled with a liquid dye, a shell wall of each of the microcapsules being composed of a resin that exhibits a temperature/pressure characteristic such that, when each of the microcapsules is squashed under a predetermined pressure at a predetermined temperature, the liquid dye seeps from the squashed microcapsule, wherein a viscosity of the liquid dye varies in accordance a degree of surface roughness of the base member such that the seeped liquid dye securely and finely fixes on the base member.
The base member may comprise a printing paper, and as the degree of surface roughness of the printing paper decreases, the viscosity of the liquid dye increases. For example, when the base member comprises an ordinary printing paper exhibiting a high degree of surface roughness, the viscosity of the liquid dye may be approximately 10 cP. Also, when the base member comprises a calendered printing paper exhibiting an intermediate degree of surface roughness, the viscosity of the liquid dye may be approximately 100 cP. Further, when the base member comprises a coated or ferrotype printing paper exhibiting a low degree of surface roughness, and the viscosity of the liquid dye may be approximately 1000 cP.
In accordance with a second aspect of the present invention, there is provided an image-forming substrate comprising: a base member; and a layer of transparent microcapsules, coated over the base member, that contains at least one type of transparent microcapsules filled with a transparent liquid dye such a liquid leuco-pigment, a shell wall of each of the transparent microcapsules being composed of a resin that exhibits a temperature/pressure characteristic such that, when each of the transparent microcapsules is squashed under a predetermined pressure at a predetermined temperature, the transparent liquid dye seeps from the squashed microcapsule and reacts with a transparent color developer to produce a given single color.
In the second aspect of the present invention, the base member may comprise a transparent plastic sheet. In this case, a layer of the transparent color developer is formed on a surface of the transparent plastic sheet formed on a surface thereof, and the transparent microcapsule layer is coated over the transparent color developer layer. Thus, the image-forming substrate can be advantageously utilized to produce a transparency film for an overhead projector. Optionally, the transparent color developer is contained in a transparent binder solution used to form the transparent microcapsule layer.
Also, in the second aspect of the present invention, the base member may comprise a sheet of paper. In this case, a layer of the transparent color developer is formed on a surface of the paper sheet, and the transparent microcapsule layer is coated over the transparent color developer layer. Thus, when the microcapsule is broken or compacted, so that a single color is exhibited due to a seepage of the dye or ink from the broken and compacted microcapsule, the exhibited single color cannot be influenced by the shell of the broken and compacted microcapsule, due to the transparency of the microcapsule shell. Optionally, the transparent color developer may be contained in a binder solution used to form the transparent microcapsule layer.
In accordance with a third aspect of the present invention, there is provided an image-forming substrate comprising: a base member; and a layer of microcapsules, coated over the base member, that contains at least one type of microcapsules filled with a dye, a shell wall of each of the microcapsules being composed of resin that exhibits a temperature/pressure characteristic such that, when each of the microcapsules is squashed under a predetermined pressure at a predetermined temperature, the liquid dye is seeped from the squashed microcapsule, wherein at least one layer of function is incorporated in the image-forming substrate for achieving a given purpose.
The function layer may comprise a sheet of transparent ultraviolet barrier film covering the microcapsule layer. In this case, a preservation of a color image, formed on the image-forming substrate, can be considerably improved due to the existence of the ultraviolet barrier film sheet. Namely, by the ultraviolet barrier film sheet, the formed color image can be prevented from deteriorating due to ultraviolet light. Preferably, the transparent ultraviolet barrier film sheet is covered with a sheet of heat-resistant transparent protective film.
The function layer may comprise a white coat layer formed on a surface of the base member to give a desired white quality to the surface. In this case, the microcapsule layer is formed over the surface of the white coat layer. Also, the function layer may comprise an electrical conductive layer formed on another surface of the base member.
In the third aspect of the present invention, the base member may comprise a sheet of paper, and the function layer may comprise a layer of adhesive formed on another surface of the paper sheet, and a sheet of release paper applied to the adhesive layer. In this case, the image-forming substrate is produced in a form of a seal sheet, a piece of which may be utilized as a seal adapted to be adhered to a post card, an envelop, a package or the like.
The base member may comprise a sheet of film composed of a suitable synthetic resin, and the function layer may comprise a peeling layer formed over a surface of the film sheet, and a layer of transparent ultraviolet barrier formed on the peeling layer. In this case, the image-forming substrate is produced in a form of a transfer film sheet, and is used together with a printing sheet of paper. Namely, an image is once formed on the transfer film sheet, and is then transferred from the transfer film sheet to the printing paper sheet. Further, a preservation of the transferred image can be considerably improved because the transferred image is coated with a thermally-fused transparent material, derived from the ultraviolet barrier layer.
The base member also may comprise a sheet of film composed of a suitable transparent synthetic resin, and the function layer may comprise a peeling layer formed on a surface of the transparent film sheet, and a layer of transparent ultraviolet barrier formed on the peeling layer, the microcapsule layer being coated over the transparent ultraviolet barrier layer. In this case, the image-forming substrate is also produced in a form of a transfer film sheet, and is used together with a printing sheet of paper. Similar to the above-mentioned transfer film sheet, an image is once formed on the transfer film sheet, and is then transferred from the transfer film sheet to the printing paper sheet. Nevertheless, after the transfer of the image from the transfer film sheet to the printing paper sheet, the remaining transfer film sheet can be utilized as a transparency film carrying a negative image. Also, a preservation of the transferred image can be considerably improved because the transferred image is coated with a thermally-fused transparent material, derived from the ultraviolet barrier layer.
The base member may comprise a sheet of board paper, and the function layer may comprise a heat-sensitive recording layer formed on another surface of the board paper sheet. In this case, the image-forming substrate can be advantageously utilized as a post card.
The base member may comprise a sheet composed of a suitable transparent synthetic resin, and the function layer may comprise a heat-sensitive recording layer formed on another surface of the transparent sheet. In this case, the heat-sensitive recording layer is used for producing a black dot on the image-forming substrate.
In accordance with a fourth aspect of the present invention, there is provided an image-forming substrate which is produced in a form of a duplicating-paper sheet or a double-recording-paper sheet. Namely, the image-forming substrate comprises: a first image-forming substrate element that includes a first sheet of paper and a first layer of microcapsules coated over a surface of the first paper sheet, the first microcapsule layer containing at least one type of microcapsules filled with a dye, a shell of wall of each of the microcapsules being composed of a resin that exhibits a temperature/pressure characteristic such that, when each of the microcapsules is squashed under a first predetermined pressure at a first predetermined temperature, the dye seeps from the squashed microcapsule; a second image-forming substrate element that includes a second sheet of paper and a second layer of microcapsules coated over a surface of the second paper sheet, the second microcapsule layer containing at least one type of microcapsules filled with a dye, a shell of wall of each of the microcapsules being composed of a resin that exhibits a temperature/pressure characteristic such that, when each of the microcapsules is squashed under a second predetermined pressure at a second predetermined temperature, the dye seeps from the squashed microcapsule; and an peeling layer interposed between the first and second image-forming substrate elements, wherein the first and second predetermined pressures and the first and second predetermined temperatures are simultaneously applied to the first and second image forming substrate elements, and the second image-forming substrate is peelable from the peeling layer.
In the above-mentioned aspects of the present invention, the resin of the shell wall may be a shape memory resin that exhibits a glass-transition temperature corresponding to the predetermined temperature.
Optionally, the shell wall may comprise a double-shell wall. In this case, one shell wall element of the double-shell wall is composed of a shape memory resin, and another shell wall element of the double-shell wall is composed of a resin not exhibiting a shape memory characteristic, such that the temperature/pressure characteristic is a resultant temperature/pressure characteristic of both the shell wall elements.
Also, the shell wall may comprise a composite-shell wall including at least two shell wall elements formed of different types of resin not exhibiting a shape memory characteristic, such that the temperature/pressure characteristic is a resultant temperature/pressure characteristic of the shell wall elements.